Corsair RM Series 550W Power Supply Review

A Detailed Look

The Corsair RM550 power supply features a scratch-resistant black matte finish and measures 160mm (6.3”) deep. The unit incorporates a single 135mm fan for cooling and all the cables are modular.

Note the fan-less operation sticker that alerts new users to the fact that the fan does not start spinning until the PSU is under moderate load. The backside panel features an open grill and includes a power receptacle and master On-Off switch. The honey comb grill allows air to exhaust out of the power supply for cooling the internal components with minimal turbulence and noise.

The RM Series 550W power supply uses a Corsair labeled 135mm fan (NR135L). Corsair says “the custom-designed fan has an optimized blade profile for low-turbulence airflow and near-silent operation even at full speed”. The fan is rated for 0.22A at 12 VDC.

The front panel contains seven modular power receptacles and one data receptacle for Corsair Link. All of the modular cables are flat, ribbon-style to help minimize air resistance and maximize case airflow. The cables are nice and long, with the 24-pin ATX and PCI-E cables measuring 25” long (63.5mm) and the 4+4-pin ATX/EPS cable measuring 26” long (66mm).

Corsair Link

If you are interested in setting up Corsair’s Corsair Link monitoring and control software on your PC, the RM Series PSU is ready with fan speed and +12V rail current monitoring. The PSU comes with a basic Corsair Link cable (long, thin cable at the bottom of the photo above) that can be connected to a Corsair Link Cooling Node or a Corsair Link USB Dongle (both optional). Previously the Corsair Link option was only available on Corsair’s premium AX Series Digital power supplies.

Under the Hood

Corsair appears to once again be using the CWT as the OEM for the RM Series 550W power supply. The PSU uses DC-to-DC converters to create the 3.3V and 5.5V outputs from the +12V rail. Note the small daughter card on the side with the heavy gauge red (+5V) and orange (+3.3V) wires coming off the top and going to the modular connector board.

The single main capacitor (Nippon Chemi-Con) on the primary is rated at 390uF, 400V, and 105°C. The secondary also features Nippon Chemi-Con electrolytic caps for filtering with a handful of solid polymer caps on the DC-to-DC converter board.

What do you think, is it OK to use this power supply in bottom-mounted-PSU cases? My concern is fan outake in limited space and directed downwar.? On loads below 50%, what's going to be with heat dissipation?

Lee, on the Specifications and Packaging page, the efficiency and fan noise curves show the x axis as sytem load (watts), but it is expressed in percentages of full load. Conversely, on the DC Load Regulation and AC Ripple page, it shows the wattage being drawn but would be more helpful in percent of full load.